The concept of limit switches for indication of the status of a component is generally known in the art. In general, indicators with electrical switches and cam members are packaged as a unit. When the limit switch malfunctions in the field one has to replace the entire limit switch. As the replacement can be time consuming as well as costly it is desirable to eliminate the system down time as well as the cost to replace an entire limit switch.
The present invention provides a field serviceable limit switch that includes a status indicator that visually alerts an observer to the condition of a particular component or components of a system such as a valve or the like in a pneumatic conveying system. The limit switch can also be used to control various other components in the pneumatic system as well as to indicate the presence of a faulty or dangerous condition in a system such as in a pneumatic conveying system.
Typically, the field serviceable limit switch can include such items as field replaceable electrical switches, field replaceable terminal blocks, field replaceable cams and field replaceable cam holders, field replaceable transducers, field replaceable indicators and a field replaceable transparent housing. By field replaceable part it is meant that an individual part can be quickly replaced by an operator in the field with few or no hand tools and without the need to replace the entire limit switch.